An increasingly preferred method of installing insulation into a building or residential structure is the method of 37 blowing in" or spraying insulation particles mixed with adhesive into the space between the outer and inner walls of the structure. The aggregate of insulation fibers and the adhesive is typically referred to as loose fill insulation.
Since the outer walls of a structure are normally installed before the inner walls, it is desirable to 37 blow in" the loose fill insulation prior to the construction of the inner walls. In this manner, no access holes for insulation installation need be placed in the inner walls once the walls are constructed. Prior placement of loose fill insulation requires the use of some means to retain temporarily the insulation between the wall framing until the inner wall can be constructed to act as a permanent retaining barrier. The prior art teaches several methods and apparatuses to provide such a temporary retaining means.
U.S. Pat. No. 4,712,347 by Sperber discloses a method and an apparatus for attaching netting to the inner side of the vertically extending, spaced studs, from floor to ceiling, and then blowing in loose fill insulation through selected holes in the netting. As the loose fill insulation is delivered into the space, it compacts together and the numerous netting holes permit the air displaced by the deposited insulation to readily escape. The netting is so constructed that it will bow outward when sufficient loose fill insulation has been received in the wall space. In this manner, the netting attains the maximum insulating effect by insuring that the particles are neither so loosely compacted to cause the surrounding air space to dissipate the heat retention effect nor so tightly compacted that there is no supplemental insulating effect created by the air surrounding the particles. In the Sperber invention, however, the netting holes may permit fibers of insulation and other fine particulate . matter to be blown or escape into the air outside of the netting when the insulation is installed.
U.S. Pat. No. 4,177,618, by Felter, is directed to a method and apparatus for installing insulation, wherein insulation is blown into vertical wall spaces formed between a permanent wall and a plastic membrane with the wall and membrane being separated and supported by the vertical studs in the structure. To prevent sagging of the membrane, which preferably is in the form of a relatively thin film or sheet of transparent plastic, the patent discloses the use of a transparent shield plate to support the membrane while the insulation is being delivered into place. The Felter invention, however, is not able to achieve the optimal density of loose fill insulation in the vertical wall spaces for the reasons that it does not employ an air permeable membrane to permit the escape of air displaced by inserted insulation particles and it does not use the sagging of the membrane as an indication of the insulation density, but uses a shield plate to prevent membrane sagging.
U.S Pat. No. 2,235,542, by Wenzel, discloses a method for installing insulation in which insulation is blown into vertical spaces formed between the outer wall and rigid laths. The wall and laths are separated and supported by the vertical studs of the structure. The Wenzel invention, however, is not a flexible barrier and permits insulation fibers and other fine particulate matter to escape through the spaces between the laths into the air outside of the laths when the insulation is installed.
Finally, U.S. Pat. No. 2,989,790, by Brown, discloses an apparatus and method for installing and packing insulation by blowing insulation into vertical spaces between the outer wall and a one inch expanded metal screen, optionally reinforced by a reinforcing strip, with the wall and screen being separated by the vertical studs of the structure. The removable screens hold the insulation in place as insulation is installed and packed into the vertical space to a desired density. Like the inventions of Sperber and Wenzel, however, the Brown invention may permit insulation fibers and other fine particulate matter to pass through the screen and escape into the surrounding atmosphere when the insulation is installed.